Eating dinner late at night is linked to obesity and poor glucose control in people with type 2 diabetes, a study has found. 

The study, “The effect of breakfast skipping and late-night eating on body mass index and glycaemic control among patients with type 2 diabetes mellitus,” was published in Cureus. 

Nutritional therapy is an integral part of the care plan for type 2 diabetes. And several studies show that weight loss promotes glucose control and reduces the risk of cardiovascular complications in people with obesity and type 2 diabetes. 

Consequently, the American Diabetes Association recommends that people with type 2 diabetes lose at least five per cent of their body weight with appropriate, personalised nutrition plans and maintain glycated haemoglobin (HbA1c) levels below seven per cent to minimise the risk of complications.

Emerging evidence shows that meal timing can promote weight loss and glucose control. Notably, adults who skip breakfast are more likely to have insulin resistance, hypertension, high blood lipids and body mass index (BMI). And late-night eating, regardless of the meal composition, is linked to a higher risk of cardiovascular disease.  

Despite these findings, no research has assessed the effect of breakfast skipping and dinner timing on BMI and glucose control in people with type 2 diabetes. Now, researchers in Saudi Arabia set out to investigate this.

They enrolled 310 adults with type 2 diabetes in Tabuk city, Saudi Arabia, in the study. The mean age of the participants was 55 years, with an average BMI of 31 and HbA1c of 8.96%. The majority (60%) had a family history of diabetes, and regarding diabetes complications, 17.4% had retinopathy, 3.2% had nephropathy, and 5.2% had coronary artery disease. 

In total, 45.2% skipped breakfast, defined as not eating between 5 am, and 10 am, and 20% ate dinner late at night, defined as eating dinner within two hours of bedtime at least three times per week. 

Participants who skipped breakfast were more likely to have higher BMIs, but there was no link between breakfast skipping and HbA1c levels. However, participants who ate late dinners were more likely to have both higher BMIs and HbA1c levels

“In the present study, nearly half of the patients with diabetes skipped breakfast, and one in five ate late in the night. Breakfast skipping and late dinner consumption were associated with obesity. However, a direct significant relationship was found between poor glycaemic control and late dinner but not breakfast skipping,” the researchers wrote. 

“The effects of late dinner intake on glycaemic control are mediated by prolonging the postprandial [after eating] glucose spike. In addition, insulin sensitivity and glucose tolerance decrease during the night,” they added.

A limitation of the study is the small sample size and that it was conducted at a single diabetes centre. 

Still, “the current results imply that meal timing is a cheap applicable preventive and therapeutic intervention for weight management and improving glycaemic target among patients with diabetes mellitus,” the researchers wrote. 

Further larger studies investigating meal sizes, meal timing and glycaemic index in people with type 2 diabetes are warranted.